This application relates generally to delivery systems for liquids and, more particularly, to a system providing for the delivery of drinking liquids to a protective mask enabling the wearer of the mask to create a closed system for ingestion without exposing the liquid to contamination.
Use of chemically active and debilitating substances requires the use of protective masks and clothing, making normal eating and drinking impossible. When using toxic chemicals, a workman may have to plan a work schedule which provides for appropriate breaks, including time to detoxify such protective clothing and allow its removal. However time-consuming and inconvenient such procedures may be, they deal with a far less life-threatening situation than that encountered by a person under attack by chemical agents. The immediacy and reliability of the protective measures required under such attacks exemplifies most sharply the inadequacies of existing liquid delivery systems. Accordingly, with the understanding that commercial, or non-combat use of the present invention is contemplated, use under combat situations will be preferably presented.
Chemical warfare has, in the past, been demonstrated to be of devastating physical and psychological effect. Chemical agents, such as toxic gases are pervasive, difficult to detect, create immediate and long-lasting disabling effects, and are available in substantial and sophisticated forms to cause a wide range of injury and/or disability from narcosis, discomfort, and disorientation all the way to paralysis and death.
To defend against such combat measures, attempts have been made to create protective clothing and protective masks in order to insulate a wearer from the effects of offensively-utilized tactical chemical agents. Where such clothing and/or masks are effective to shield or filter the particular chemical agent involved, the wearer will be protected so long as the integrity of the protective garb remains intact.
It is characteristic of chemical agents that, once deployed, they may remain effective for a substantial period of time afterward before naturally occurring atmospheric and meteorologic action either disperses, dilutes, or removes them from the environment. As an example, certain chemical substances dispensed in aerosol form may be degraded or altered by the action of direct sunlight, while others, being water soluble, may be "scrubbed" from the atmosphere and/or landscape during rainstorms. Nevertheless, it is an accepted consequence of such forms of warfare that protective clothing, once donned, may have to be worn for an indeterminate amount of time until it is established that the danger to the wearer has abated.
Protection of the wearer is only one aspect of such protective garments. Another consideration is the ability of the wearer to carry out assigned duties even when prolonged use of such protective clothing is required. This means that such garments must not only enable the wearer to see and to communicate, but, advantageously, must also make some provision for the ingestion of liquids in order to replace those liquids lost by the body through perspiration which may be heightened by the wearing of protective clothing of impermeable or semipermeable characteristics, and by increased or stimulated body reactions resulting from participation in frightening or stressful situations.
Exemplary of a protective mask designed to meet such emergency situations is the mask illustrated and discussed in U.S. Pat. No. 3,731,717, issued May 8, 1973. Other versions of such masks include a full, overlapping hood which completely covers the wearer's head, neck, and portions of the shoulders, but which depends for its effectiveness upon a system of air filtration typified by the mask shown in the above-mentioned patent.
The wearer's incoming air supply is directed through a canister containing activated charcoal or other mechanical and chemical filtering agents selected to be effective against the particular chemical agent or agents expected to be encountered. Other portions of the mask must form a substantially air-tight protective fit about the wearer's face and head. This is important because some chemical agents are absorbed not only through the respiratory system, but may enter the body through exposed skin surfaces. Transparent eye pieces are provided to enable the wearer to see through the mask, however, the range of vision is somewhat obstructed by the nontransparent portions of the mask.
Thus, when the protective mask is properly in place, the wearer is unable to eat or drink normally without breaching the integrity of the mask's protective features. This poses a critical problem, particularly with respect to body fluids, which must be constantly and continuously replenished to avoid the serious effects of dehydration.
The above-mentioned patent provides a means by which the wearer of such a mask may ingest liquids without requiring removal of the mask. As a part of the mask construction, a mouthpiece mounted on the inside of the mask is positionable to engage the wearer's mouth. An inlet tube attached to the mouthpiece extends through an air-tight fitting to the exterior of the mask, with the tube terminating in a plug.
A standard U.S. Army canteen is fitted with a cap having a built-in fitting to accept the plug formed at the end of the inlet tube so that when the plug is inserted into the cap, a closed system is created which includes the interior of the canteen, the interior of the cap and plug the inlet tube, and the mouthpiece. However, use of such a system provides serious inconveniences and disadvantages which serve to complicate the procedure for obtaining such liquids and, in the case of a combat soldier, exposes the soldier to unwarranted hazards and dangers encountered during the conduct of the soldier's assigned mission.
As set forth in said patent, and as set forth in U.S. Army instruction manuals, such as No. 3-54 EL/2, at ORDG. 1038-29, pp. 2-49 to 2-50, use of the above-described system requires the soldier to remove the canteen from its holder, remove the protective flap covering the cantten cap, visually locate the plug at the end of the drinking tube and visually locate the cap on the canteen, insert the plug into the cap, and elevate the canteen above the level of the mouthpiece so that the liquid will flow under the influence of gravity from the canteen, down the tube, and through the mouthpiece. This type of closed system is further complicated because the canteen itself cannot be vented to the atmosphere or else the liquid contained therein will become contaminated by the chemical agent present. This means that constant flow will not take place by gravity alone.
In order to remedy this situation, the user of such a system is instructed to blow through the mouthpiece in order to inject air into the canteen, and to thereafter suck liquid from the canteen via the drinking tube and mouthpiece. Such blowing and sucking operations are tiring and time-consuming, and seriously limit the rate at which the liquid can be drained from the canteen. Under conditions which have already created physical and psychological stress, such as those encountered on the battlefield, any additional physical effort should preferably and necessarily be avoided.
Another disadvantage of the above described system is that the user must use two hands, which means whatever activity the user is carrying out must be interrupted. The user must also raise the canteen above the level of the mouthpiece and hold it there in a tiring and awkward posture. Apart from the physical effects and consequent fatigue, this means that the user may be forced to maintain a relatively vulnerable posture in order to perform so simple an act as the taking of a drink.
When the user has finished drinking, the plug must be removed from the canteen cap, the protective flap must be sealed across the cap socket, and the canteen must be returned to its holder. During this operation, of course, the cap and plug are exposed to possible contamination by any chemical agents present in the air, and must be decontaminated prior to connection every time a drink is required.
Given the nature of certain chemical agents, the toxic effects of such agents are enhanced when they are utilized at night, particularly those agents which are degraded by higher temperatures or direct sunlight. This means that use of protective garments and liquid delivery systems for such garments may most frequently occur when visibility is at its poorest, thereby jeopardizing the secure and correct decontamination and connection of the above-described system.
Accordingly, the need exists for a liquid delivery system which would substantially overcome the above-identified problems, thereby adding to the security and continued health and well being of one forced to adopt the use of such protective clothing and masks for indeterminate periods of time. The need also exists for such a delivery system to be readily adaptable to protective equipment already in widespread use, making deployment of such a system compatible to both old and newly-manufactured equipment.